1. Field of the Invention
The present invention relates generally to interface apparatus in a computer system, and more particularly to an interface apparatus employing a video tape drive to back-up a disc drive having a non-removable magnetic storage medium, including error detecting and correcting circuitry, and the computer system employing same.
2. Description of the Prior Art
Conventional data processing systems have employed a computer or central processing unit (CPU), one or more memories for storing data on a magnetic storage medium and a controller for controlling and synchronizing the transfer of data within the system. One particular configuration of such a system includes a disc drive having a memory in which the magnetic transducers and magnetic discs are hermetically sealed in a cartridge and a controller. This configuration is commonly known in the industry as a "Winchester." A disadvantage of relying solely on a single memory to store data is the severe consequences associated with losing the data recorded on the disc. This could arise when a magnetic transducer crashes into a portion of the recording surface of the magnetic disc. For example, the data may comprise the unique business information, such as sales, gross receipts, expenses, tax records, etc., of a business or corporation. Hence, back-up memories have been employed in some data processing systems.
In the past, back-up systems have been relatively costly and in many cases have been unreliable in that when used in a back-up situation, they provided back-up data that included errors and, hence was not identical to the data originally stored on the magnetic disc.